ALKALINE AND ALKALINE/OXIDATION PRE-TREATMENTS OF SPRUCE WOOD PART 2: PHYSICAL PROPERTIES OF THE PRETREATED WOOD AND THEIR INFLUENCE ON ITS DIGESTIBILITY UNDER CONDITIONS OF KRAFT COOK

摘要

A series of comparable specimens of spruce wood were submitted to chemical pre-treatments. Chemical pre-treatments were carried out with diluted sodium hydroxide, or sodium hydroxide and then with diluted hydrogen peroxide, or per-acetic acid. All pre-treatments modified the physical properties of wood and caused its weight loss. The pre-treatments resulted in an increase in the facial swelling, coefficients of axial permeability and diffusion under stationary conditions of determination at ambient temperature. A deep, almost total deacetylation of spruce wood due to the pre-treatments influenced apparently the uptake of water by the pre-treated wood. All the mentioned alterations in physical properties of the pre-treated material are casually connected with its chemical changes and reflected improved digestibility of spruce wood under conditions of kraft cooks.